diff options
Diffstat (limited to 'net/netfilter')
-rw-r--r-- | net/netfilter/core.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 5d29d5e2362..27f639f3ac2 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -222,6 +222,28 @@ copy_skb: } EXPORT_SYMBOL(skb_make_writable); +u_int16_t nf_csum_update(u_int32_t oldval, u_int32_t newval, u_int32_t csum) +{ + u_int32_t diff[] = { oldval, newval }; + + return csum_fold(csum_partial((char *)diff, sizeof(diff), ~csum)); +} +EXPORT_SYMBOL(nf_csum_update); + +u_int16_t nf_proto_csum_update(struct sk_buff *skb, + u_int32_t oldval, u_int32_t newval, + u_int16_t csum, int pseudohdr) +{ + if (skb->ip_summed != CHECKSUM_PARTIAL) { + csum = nf_csum_update(oldval, newval, csum); + if (skb->ip_summed == CHECKSUM_COMPLETE && pseudohdr) + skb->csum = nf_csum_update(oldval, newval, skb->csum); + } else if (pseudohdr) + csum = ~nf_csum_update(oldval, newval, ~csum); + + return csum; +} +EXPORT_SYMBOL(nf_proto_csum_update); /* This does not belong here, but locally generated errors need it if connection tracking in use: without this, connection may not be in hash table, and hence |